# Multimetal Doping and Heterostructure Engineering of RuO2 for Durable and Efficient Oxygen Evolution

## TL;DR

This paper introduces a new catalyst for water splitting that is efficient and durable, using a combination of metals and structural engineering to improve performance.

## Contribution

The novelty lies in combining multimetal doping with heterostructure engineering to create a durable and efficient oxygen evolution catalyst.

## Key findings

- The MnCoNi–RuO2 catalyst achieves low overpotentials and improved stability compared to commercial catalysts.
- The catalyst retains high activity in both acidic and alkaline conditions and operates effectively for 100 hours in an electrolyzer.
- DFT calculations show that multimetal doping lowers reaction barriers and enhances stability against metal dissolution.

## Abstract

The oxygen evolution reaction (OER) is the primary kinetic bottleneck in water electrolysis, requiring catalysts that are both efficient and durable. Here, a MnCoNi–RuO2 (MCN–RuO2) heterostructured catalyst synthesized via a controlled impregnation–annealing–etching process that integrates multimetal doping with mixed‐phase oxide formation is reported. Structural analyses reveal a RuO2 host lattice interfaced with MnO and spinel‐type CoNiO
x
domains, generating lattice distortion, oxygen vacancies, and defect‐rich interfaces that tune the electronic structure and enrich active sites. Electrochemical tests demonstrate overpotentials as low as 200 mV at 10 mA cm−2, a low Tafel slope, and markedly improved stability relative to commercial RuO2 and IrO2. The catalyst also retains high activity under acidic conditions and, when implemented in an anion exchange membrane water electrolyzer, sustains industrially relevant operation for 100 h with minimal degradation. Density functional theory calculations reveal that multimetal incorporation drives charge redistribution, lowers the work function, and shifts Ru‐4d states, reducing the barrier for the rate‐determining *O → *OOH step while enhancing stability against Ru dissolution. These findings establish MCN–RuO2 as a versatile, Ir‐free platform and demonstrate multimetal doping with heterointerface engineering as a powerful strategy for designing next‐generation OER catalysts.

A MnCoNi–RuO2 heterostructure engineered through multimetal doping and mixed‐oxide interface formation generates lattice distortion, oxygen vacancies, and electronically optimized active sites for the oxygen evolution reaction. MnCoNi–RuO2 achieves high activity and durability across alkaline and acidic media, sustaining 100 h (AEMWE) anion exchange membrane alkaline electrolysis operation. Density functional theory reveals charge redistribution and lowered *O → *OOH barriers driving electrocatalytic performance.© 2026 WILEY‐VCH GmbH